Koa middlewares

app.js

var koa = require('koa');
var app = koa();

app.use(function *responseTime(next){
  var start = new Date;
  yield next;
  var ms = new Date - start;
  this.set('X-Response-Time', ms + 'ms');
});

app.use(function *logger(next){
  var start = new Date;
  yield next;
  var ms = new Date - start;
  console.log('%s %s - %s', this.method, this.url, ms);
});


app.use(function *response(next){
  yield next;
  this.body = 'Hello Nodebp!'
});

app.listen(3000);

app_express.js

var express = require('express');
var app = express();
 
app.use(function responseTime(req, res) {
  var start = new Date();
  var end = res.end;
  res.end = function() {
    var ms = new Date() - start;
    res.set('X-Response-Time', ms + 'ms');
    end.apply(res,arguments);
  };
  req.next();
});
 
app.use(function logger(req, res) {
  var start = new Date();
  var end = res.end;
  res.end = function() {
    var ms = new Date() - start;
    console.log('%s %s - %s', req.method, req.url, ms);
    end.apply(res,arguments);
  };
  req.next();
});
 
app.use(function response(req, res){
  res.send('Hello Nodebp!');
});

var server = app.listen(3000, function() {
    console.log('Listening on port %d', server.address().port);
});

express version of this: https://gist.github.com/oroce/03349e92eb0f6d282d0e